Material level indicator



.-J. B. GAFFNEY MATERIAL LEVEL INDICATOR Filed July 7`, 1945 April 23,1946.y

IN: l l K\ l l I y B Patented Apr. 23, 1946 MATERIAL LEVEL lINDICATORJoseph B. Gaffney, Hokendauqua, Pa.,lassignor to Fuller Company,'Catasauqum Pa., a corpora tien of Delaware Application July 7, 1943,'Serial N0. 493,746

(Cl. .17T-'311) 4 Claims.

The present invention relates to `indicators or electrical switchoperating mechanisms and more particularly low level bin indicators foruse in connection with bins or bunkers for the storage of pulverulentmaterials, to open or close electrical circuits when .the storedpulverulent, crushed or granular material reaches or falls below apredetermined desirable level. The indicator may be used., ior example,in storage bins for pulverized coal, cement, lime, flour,

starch and other materials having similar physical characteristics, .toopen or close signal .circuits and circuits controlling the 'flow in,pulverulent .material Aconveying systems.

Pulverulent materials have peculiar characteristics which make itdifficult to obtain accurate indications of the safe minimum quantity ofmaterial actually in storage. When delivered to the bin or bunker theyare frequently in an aerated state and are so fluid in character thatthey 4surge and splash. Again the material in a bin is likely to shiftin large masses iand during such shifting exert relatively large forces`on anything in its way or resisting such .movement.

`It has been Vthe practice to mount .low level indicators by running thesignal elements .down close to the side of a bi-n with short .bracesextending out from the side to hold them 4rigidly in position. Thisbracing enabled the vindicator to resist motion of the shifting mass.Frequently, however, it is not desirable to mount the indicator close tothe side of bin since false or highly inaccurate readings sometimesresult. This may be caused by piping or channeling of the material uponWithdrawal, in which case the material stands almost vertically alongthe side Walls. Under such conditions, with the indicator attached tothe side Wall, an indication is given that the bin contains materialwhen as a fact very little or none can be withdrawn.

It is accordingly among the objects of the present invention to providean indicator mounting means which overcomes the dirliculties describedabove and assures positive and reliable operation of the indicator atall times, so that it may be used as a remote control device with aminimum of supervision.

The present invention is accordingly directed to a mounting for a lowlevel indicator which will center it in the bin at the point where themaximum withdrawable material is most likely to be and at the same timepermit it to move freely with the shifting mass of material. Such aconstruction will permit the indicator to be where vthe material is andso 'eliminate false indications and at the same timeA removev thenecessity furthe bracing which 'in some installationsr is quitecumbersome and togetherl with its assembly on the Ajob 'may costsubstantially more thanY all "the rest oi the indicatory combined.

vThe solution Ato the problem Was found to be to protect 'the dependingshaft ofl thelow level indicator by imean's of `a relatively largesizepipe surrounding it' and suspend the indicator and protecting pipe fromoverhead supports in such a Way that the assembly could swing like a,pendulum when disturbed by a mass movement of the .material in Ythebin. Such a mounting is provided by .gimbals somewhat Ysimilar to thoseused to mount a compass. j

v.Further consideration Vindicated. the advisability-oi a change inthetype of indicator paddle Ynormally used. Formerly it had been thepractice to Aprovide a paddle guard which resembled an umbrella over thepaddle .to protect it from material likely to .grab .and exert apullupon it.

For Ya better understanding .of the invention reference may be had tothe accompanying drawing which .is illustrative in. character and is notto be taken as limiting. A l l Fig. l is an elevation of the indicator.mounted in a bin orbunker lled with material and sectioned.

Fig. 2 lis fa .plan view of the indicatormounting means.

Fig. 3 is an elevation of the indicator mounting means partly sectionedalong line l3--i of Fig. 2 to more clearly show the parts of the device.

Fig. 4 is a section detail along line 4-4 of Fig. 2.

In Fig. 1 is seen a catenary coal bin Il), having an inlet II and adischarge opening l2. Channel members I3 extend across inlet Il and haveWelded or otherwise fastened to their under surfaces mounting channelsI4 on which are bolted trunnions l5. Stub shafts I6 are journaled intrunnions I5 and are welded or otherwise fastened to diametricallyopposite sides of outer ring I1, which likewise mounts inwardlyextending stub shafts I8 the axis of which makes an angle of degreeswith that of stub shafts I6. The inwardly extending portions of stubshafts I8 are journaled in trunnions i9 mounted on the under side ofinner ring 2b.

Housing 2| is bolted to inner ring 2Q and contains the switch mechanismof the low level indicator. The details of one form of this switchmechanism may be seen in United States Patent No. 2,116,075 granted toLenhart on May 3, 1938 to which attention is invited for furthervillustration and in the interest of completeness outlet I 2, voids willappear in the lower portion of bin I0 which will be lled by the shiftingof material 26. As material 26 shifts, protecting pipe 23 and itsenclosed rod 24 mounting paddle 25 are free to move with the material 26as shown by the dotted lines in Fig. 1. "Ihiseliminates all necessityfor expensive and obstructing bracing Y withinthe bin I0. This freedomof movement in all directions is made possible by inner and outer ringsor gimbals and I1 and the pivoting of stub shafts I8 and I6 in theirrespective trunnions I9' and I5. Whenthe material 26 drops below` paddlewhich then hangs substantially vertically from housing 2I and gimbals orrings I'I and 20, the paddle 25 is free to rotate and actuate the signalmechanism in housing 2l. The signal mechanism may be connected tooperate both a visual indicator and an automatic or manual switchmechanism to supply additional material 26 and refill binIO.

From the above description other means of solving the problem will besuggested. One such means which may be used where loads are light wouldbe to substitute a flexible plate of rubber or like material for one orboth of rings I1 and 20. Such a plate would have substantial thicknessof as much as an inch or an inch and a half and could be directlymounted on channels I4. Housing 2| would be fastened to the rubber androd 22 depend through a hole in its center. A perhaps betterconstruction would be to have the rubber in the form of a disk of thesame diameter as ring I'I and retain trunnions I5 and stub shafts I6. Areinforcing element may be desirable where stub shafts I6 are mounted inthe rubber disk.

I claim:

1. In an electrical indicator for pulverulentmaterial storage binsincluding an electric motor,

a support therefor, an indicator arm, means for rotating said arm fromthe electric motor, said arm extending downwardly from the motor andadapted to have its lower end portion embedded in pulverulent materialin the bin, rigid protecting means depending from said support andsurrounding the arm for the major portion of the length thereof toshield it from contact with pulverulent material in the bin and meansextending in a non-axial direction from the lower end portion of the armbeyond the rigid protecting means to engage pulverulent material whenthe lower end portion of the arm is embedded in such material in thebin; the improvement which comprises a universal mounting for the motorsupport', whereby the indicator arm and the rigid protecting meanstherefor can swing, with a shift of the pulverulent material in the bin,in any direction from the vertical.

2`. An electrical indicator for pulverulent-material storage bins as setforth in claim 1 iny which the universal mounting comprises concentricrings pivoted about mutually perpendicular axes.

3. VIn an electrical indicator for pulverulentmaterial storage binsncluding an electric motor, a housing therefor, said housing having adepending flange, an indicator arm, means 'for rotating said arm fromthe electric motor, said arm extending downwardly from the electricmotor and adapted to have its lower end portion embedded in pulverulentmaterial in the bin, rigid protecti tually perpendicular axes.

ing means fastened to said depending flange and surrounding theindicator arm for the major portion of its length to shield it fromcontact with pulverulent-material in the bin and means extending in anon-axial direction from the lower end portion of the arm, beyOnd therigid protecting means to engage pulverulent material when the lower endportion of the arm is embedded in such material in the bin; theimprovement which comprises a universal mounting for the motor housing,whereby the indicator arm and the protecting means therefor can swing,with a shift of the pulverulent material in the bin, in any i' directionfrom the vertical.

4. An electrical indicator for pulverulent-ma' terial storage bins asset forth in claim 3 in which the universal mounting for the motorhousing comprises concentric rings pivoted about mu- JOSEPH B. GAFFNEY.

